This invention relates to a method for adjusting an ink fountain in a printing press before the printing operation and to the ink fountain itself.
In general, an ink fountain has a ductor blade which is divided into a plurality of pieces or regions. The ductor blade is disposed obliquely along an ink fountain roller or duct roller so as to form a wedge-like space as viewed in the lateral direction of the ink fountain. In the wedge-like space, ink for printing is stored and a certain amount of ink is fed therefrom to an inking arrangement through a gap between the distal end of the ductor blade and the surface of the duct roller.
Such an ink fountain is disclosed in U.S. Pat. No. 4,344,360, in which when an operator adjusts the ink gap before the printing operation, he operates adjusting screws to move the distal end of a ductor blade toward and away from the surface of a duct roller on the basis of data which are obtained from the rates of pattern areas on a printing plate, a film original or the like. The rates of pattern areas can be obtained by a pattern area measuring apparatus which detects the rate or proportion of the area occupied by a color to be printed in a predetermined region on the printing plate, the film original or the like.
That is, the operator operates the adjusting screws while observing a card on which the data of rates of pattern areas are written. However, there are many adjusting screws and the operator must pick up a datum corresponding to each adjusting screw to be adjusted from the card. Accordingly, there is a possibility that the operator might pick up a wrong datum therefrom.
In addition to this type of ink fountain, there has appeared an ink fountain which can automatically adjust the adjusting screws. In this new type of ink fountain, a drive motor is connected to each of the adjusting screws and is remote-controlled on the basis of data of rates of pattern areas. This mode of adjustment affords a remarkably short adjusting time. However, in this mode of adjustment, there must be provided many drive motors whose number corresponds to that of adjusting screws. In addition, a controller for controlling each of the drive motors is needed. Accordingly, this adjusting mode cannot be adapted easily to conventional ink fountains. If it were to be adapted to conventional ink fountains, it would require a great change in the construction of the fountains.